Commercial grade high purity oxygen has a nominal purity of 99.5 percent. Generally commercial grade high purity oxygen is produced by the well known cryogenic fractional distillation of air, most often using a stacked double column arrangement. The commercially available high purity oxygen is suitable for use in a great many applications.
Commercial grade high purity oxygen contains a small amount of impurities. The impurities include both light impurities having a vapor pressure greater than oxygen, and heavy impurities having a vapor pressure less than oxygen. Occasionally oxygen is required which has significantly less impurities than the commercially available high purity oxygen. In these instances, high purity oxygen has heretofore been upgraded to ultra high purity oxygen by means of catalytic combustion.
The electronics industry requires the use of ultra high purity oxygen for many applications. However, the conventional catalytic combustion method for producing ultra high purity oxygen is not suitable because of the consequent production of particulates generated from the granulated catalyst.
It is desirable therefore to have a process and apparatus to produce ultra high purity oxygen without need for the use of catalytic combustion.
Accordingly, it is an object of this invention to produce ultra high purity oxygen without need for the use of catalytic combustion.
It is a further object of this invention to produce ultra high purity oxygen by the upgrading of high purity oxygen produced by the cryogenic fractional distillation of air.